Apparatus for recovering volatile materials



Feb. 12, 1952 E. F. DREW 2,585,638

APPARATUS FOR RECOVERING VOLATILE MATERIALS Original Filed Aug. 23, 1945IPEMO #441 OVER/"10W coo $754M A INVENTOR. [RA/57 F 025w Patented Feb.12. 1952 APPARATUS FOR RECOVERING VOLATILE MATERIALS Ernest F. Drew, NewYork, N. Y., assignor to E. F. Drew & 00., Inc., New York, N. Y., acorporation of Delaware Original application August 23, 1945, Serial No.612,275. Dividedrand thisapplication July 24, 1948, Serial No. 40,504

4 Claims. (Cl. 23-283) .The present invention is directed to oils and jfats and more particularly to an apparatus for the treatment of wasteand objectionable vapors emanating from the splitting of such oils andfats" for the production of free fatty acids. The application is adivision of copending applicaation Serial No. 612,275 filed August 23,1945, entitled Method of Recovering Volatile Materials, now Patent No.2,471,942.

In said application the prior art was discussed inwhich it has beencommon practice to treat vegetable and other oils and fats which areglyc'erides ofmixed higher fatty acids in order to hydrolyze the sameand to split the fatty acids from the glycerine. This has beenaccomplished by the use of such splitting agents as mineral acids,Twitchell reagent and the like, under the application of heat andsometimes of pressure.

Such processes give rise to vapors having undesirable and. oftendisagreeable odors which in many cases-presented a great nuisance to thesurrounding community if such vapors were allowed to escape during theprocess. Such vapors include in most cases, in addition to the disagree"able odo1"s,vapors of water, mineral acid, fatty acid and glycerine.derived from the sulphonating or splitting agent Some of the vapors mayhe used in the process. Attempts have been made to prevent the diffusionof such vapors into the outside air both to abate the nuisance caused bysuch vapors in a community and to prevent the unnecessary loss i ofvaluable ingredients in said vapors. However, efforts to economicallyrecover such vapors have present invention to provide a means forfractionating the fatty acids of certain oils and fats whereby a mixtureof lower fatty acids contained in such oils may be recovered.

In practicing the present invention, there is provided an absorptiontower into which the waste vapors are led and allowed to pass upwardlythrough the same. In the center of the tower is an absorption unithaving a solution ofcaus'tic soda passing downwardly counter-current tothe upwardly traveling vapors. A body *of caustic alkali solution ismaintained in the bottom of the tower with a pump or the like forcirculating the same over the absorption unit. The cycle of treatment ismaintained until a certain concentration of fatty acid has been absorbedin the caustic alkali in the form of soap. Usually from 4 to 5% of fattyacid in the solution is considered sufficient to enable economicalrecovery of the fatty acid from the solution. It is desirable to have aminimum concentration of caustic alkali in the solution of about 2% inorder to avoid interference by foaming of the soap in the solution. Itis also important that the solution being circulated be kept at arelatively high temperature, usually in the neighborhood of the boilingpoint of water in order that there shall be a minimum of absorption ofwater vapor from the mixed vapors being treated. This contributesgreatly to the effectiveness of the operation.

'Such a process enables the recovery of substantially all of the fattyacids which may be present in the vapors and the absorption is in such aform that the fatty acids may be readily recovered therefrom.Simultaneously therewith, the objectionable odors present in the vaporsare also absorbed and are eliminated from the atmosphere. When such oilsas the coconut type of oil is treated, the vapors thereof contain thelower fraction of the fatty acids present in the original oil and theabsorption of such fatty acids from the vapors is capable of providingthe mixed lower fatty acids, which as a unit are eminently suitable foradaptation in commerce, as for example, in the form of the polyalkylencglycols for use as plasticizers.

In the accompanying'drawing constituting a part hereof and in which likereference characters indicate like parts, the single figure is a'vertical cross-sectional view taken through an apparatus made inaccordance with the present application, some parts being shown inelevation and other parts being shown diagrammatically. In the treatingvessel I, there is performed the operation of splitting the oil or fatby any of the usual reagents. The vapors produced in the-process passthrough duct or pipe 2 which extends vertically upward through thecentral part of the bottom 3 of a vertical tower 4. The upper end 5 ofduct 2 is provided with a series of openings to allow the vapors toescape into the tower. A cap; is' provided at the top of pipe 2 toprevent accidental en'trance of solution into the same: g

along with the same.

in the tank becomes too high, the liquid passes through pipe I intooverflow-chamber I l and out through l2 for re-use.

In the bottom 3 of the tower which slopes slightly and at the lowestpoint thereof, there is an exit opening 13 and a :pipe is leading .to

pump IS. A pipe I6 from the pump has a check valve Il therein, said pipeextending upwardly and then horizontally as shown at [8, passing intothe tower at an intermediate point thereof intoqspace 19. .A spray headis adapted to .disseminate liquid into the tower. .Betweenwhorizontalperforated platesi2l and 22 .isan absorption unit 23 of 'any suitabletype, such as the well-known Raschig .rings, .suitably packed in orderto cause liquid to passdownwardly over the surfaces in contact with thevapors passing upwardly in the unit.

Above the spray 20 are a pair of similar horizontal perforated plates*24 and 25 having between the same a packing or filling 26 which mayalso be of Raschig rings. The spent gases and vapors 'after'passage'through the unit 26 enter'upper end 21 of the tower and passout therefrom through opening or stack 28.

, In the operation of the apparatus for thetreatmerit of the wastevapors, the caustic soda solution is maintained at about the boilingpoint ,of

'water and is continuously circulated by pump ll. Vapors are allowed topass throughthe duct 2 out of openings 5 and upwardly through absorptionunit 23. The vapors come into intimate contact with the hot caustic sodasolution whereby all acid vaporsare absorbed and recovered from thevapors. Because of the high temperature of the solution, very little, ifany, water vapor is absorbed therein and'itpasses up out of theabsorption unit with other unabsorbed substances. The circulation of theliquid is continued, causing a gradual building up in the solution offatty acid soaps. When the fatty acid content reaches l'to 5% or higherand the caustic soda content is down to about 2%, the solution may beremoved for the recovery of the fatty acids. A 'fresh caustic sodasolution is introduced and the cycle is continued.

Due to the fine sub-division of the solution as it is sprayed from-thespray head into 'the tower, and the upwardly flowing current of gasesand vapors, some of the solution may be carried Therefore, the sprayremoval unit 26 is provided, which catches the spray on the packingmaterial and the solution flows downwardly and eventually reaches theabsorption unit. The temperature of the spray removal unit is alsopreferably maintained at about the boiling point of water so as not todilute the solution. Therefore, the gases passing out through stack '28contain substantially all of the water vapor which had been presentin-the vapors in duct 2.

The solution "containing "the soaps may :then

the acidulated as by the use of sulphuric acid-in the usual. manner tosplit-the "soap :stock. The resulting product contains at least 99% offatty 4 acids and they may be used as such or be redistilled orotherwise treated for further purification.

The present invention is adapted for use in all cases where fats andoils :ofia glyceride fatty acid typeare split to recover fatty 'acids.The invention is particularly adapted for use where the coconut type ofoil is split. Such oils contain a substantial amount of lower fattyacids having-6, 8, '10, '12 and 14 carbon atoms in addition to the fattyacids of 16 and 18 carbon atoms which are present in practically allvegetable and animal oils. It has been found that the vapors produced inthe splitting of, say, coconut oil, contain only the lower fatty acidspresent in such -oil having .from 6 to 12 carbon atoms. When such amixture of fatty acids is recovered first in the form of soap and thenin the form of the mixture of free fatty acids, the approximatecomposition thereof is as follows:

' Per cent 'Caproic (C6) "15.9 Caprylic '(Ca) "'5'6L8 Capric (C10) 119.4Lauric-l-etc. (012+) 7.9

Therefore, the present invention .IPI'OVidCS .a simple and inexpensivemeans for Ifraction'ating the fatty acids of coconut oil to recoveramixture of lower fatty acids- Thesehave been found eminently suitablefor use as the :mixedpolyethylene glycol esters, as plasticizers forvarious resinous materials, synthetic rubber and the like.

Although the invention .has been describedby use of a certain specificexample, the invention is not limited thereto as various modificationsin the process and the apparatus :may "be-made within the scope of theinvention. For-instance, the caustic soda solution may be used1until-the concentration of. the fatty acid is greater than thatspecified herein, or the caustic soda content thereof may be replenishedcontinuously or :in-'

termittently. Also, the process may zbeioperated so that a part of thecaustic soda is withdrawn for the recovery of fatty acids and the volumereplenished by fresh caustic soda solution. Other alkalis than sodiumhydroxide may, of course, be used in the process. The minimumconcentration of alkali may be less'than 2% in some cases.

The absorption units maybe of .differentcharacter and under suitableconditions the'units may be entirely omitted where the tower issufficiently high and the absorption of .the'fatty acids andobjectionable odors is-sufficiently completewithout the necessity ofpacking in the tower; The tower need not be made in a single vertical"unit but one or more of the elements suchas the container, absorptionunit and'spray removal unit may be made separately and suitably coupledtogether. Such units may be'placed in a-vertical position or they may behorizontallydisplaced. In'place of steam, other meansmay 'beusedfformaintaining the desired temperature of the circulating solution.

The invention is applicable not onlyito vapors resulting from thesplitting of oils 'and fats-but also to vapors arising fromvarious'otherwperations on glyceride oils, fats, fatty acids, soapstock, and others, wherein the 'vaporsicontainia'cid constituents, watervapor: and objectionable odors. These and other-changeszinxthedetailsbfithe practice of the inventionmay ibe mad-e'without departingfrom Y the spirit :thereof :and the iinvem tion is to -'be broadlyconstrued :and not ":to :be

limited except by the spirit of the claims appended hereto.

I claim:

1. An apparatus for treating waste gases and vapors from the hydrolysisof oils and fats comprising a set of three vertically disposed chambersconstituting a single tower, perforated plates between said chambers, aninlet pipe for said vapors extending centrally through the bottom of thelowest chamber and terminating at the top thereof, the top of said pipehaving perforations in its sides and a cap on the upper end thereof, aspray head in the top of the intermediate chamber and packing materialin the lower part thereof, a pipe connection from said spray head to thebottom of said lowest chamber, an overflow pipe in the upper part ofsaid lowest chamber adapted to draw oif liquid from a point just belowsaid perforations, distance between said overflow pipe and the bottom ofsaid lowest chamber adapted to permit a deep body of liquid to bemaintained therein, the area of said inlet pipe submerged in said liquidbeing suflicient to provide material heat exchange with said liquid, aheating coil for maintaining said body at about the boiling point ofwater surrounding said inlet pipe below said overflow pipe, packingmaterial in the uppermost chamber, and an exit stack centrally of thetop of said uppermost chamber.

2. An apparatus for treating waste gases and vapors from the hydrolysisof oils and fats com prising a set of three vertically disposed chambersconstituting a single tower. perforated plates between said chambers, aninlet pipe for said vapors extending centrally through the bottom of thelowest chamber and terminating at the top thereof, the top of said pipehaving perforations in its sides and a cap on the upper end thereof, aspray head in the top of the, intermediate chamber and packing materialin the lower part thereof, a pipe connection from said spray head to thebottom of said lowest chamber, a pump in said connection for causingliquid to flow through said spray head, an overflow pipe in the upperpart of said lowest chamber adapted to draw ofi liquid from a point justbelow said perforations, distance between said overflow pipe and thebottom of said lowest chamber adapted to permit a deep body of liquid tobe maintained therein, the area of said inlet pipe submerged in saidliquid being suflicient to provide material heat exchange with saidliquid, a heating coil for maintaining said body at about the boilingpoint of water surrounding said inlet pipe below said overflow pipe,

packing material in the uppermost chamber, and a an exit stack centrallyof the top of said uppermost chamber.

3. An apparatus for treating waste gases and vapors from the hydrolysisof oils and fats comprising a set of three vertically disposed chambersconstituting a single tower, perforated plates between said chambers, aninlet pipe for said vapors extending centrally through the bottom of thelowest chamber and terminating at the top theret e top of said p pehaving p rtorat oas in its sides and a cap on the upper end thereof, aspray head in the top of the intermediate chamber and packing materialin the lower part thereof, the space surrounding said spray head beingfree from packing material, a pipe connection from said spray head tothe bottom of said lowest chamber, an overflow pipe in the upper part ofsaid lowest chamber adapted to draw off liquid from a point just belowsaid perforations, distance between said overflow pipe and the bottom ofsaid lowest chamber adapted to permit a deep body of liquid to bemaintained therein, the area of said inlet pipe submerged in said liquidbeing sufiicient to provide material heat exchange with said liquid, aheating coil for maintaining said body at about the boiling point ofwater surrounding said inlet pipe below said overflow pipe, packingmaterial in the uppermost chamber, and

an exit stack centrally of the top of said uppermost chamber.

4. An apparatus for treating waste gases and vapors from the hydrolysisof oils and fats comprising a set of three verticallydisposed chambersconstituting a single tower, perforated plates between said chambers, aninlet pipe for said vapors extending centrally through the bottom of thelowest chamber and terminating at the top thereof, the top of said pipehaving perforations in its sides and a cap on the upper end thereof anda cap thereon, a spray head in the top of the intermediate chamber andpacking material in the lower part thereof, a pipe connection from saidspray head to the bottom. of said lowest chamber, an overflow pipe inthe upper part of said lowest chamber adapted to draw off liquid from apoint just below said perforations, distance between said overflow pipeand the bottom of said lowest chamber adapted to permit a deep 1 bodyofliquid to be maintained therein, the area of said inlet pipe submergedin said liquid being suflicient to provide material heat exchange withsaid liquid, a heating coil for maintaining said body at about theboiling point of water surrounding said inlet pipe below said overflowpipe, packing material in the uppermost chamber, and an exit stackcentrally of the top of said uppermost chamber.

ERNEST F. DREW.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,226,898 Lummus May 22, 19171,470,116 Gray Oct. 9, 1923 1,928,495 Jacobson Sept. 26, 1933 2,161,122Anderson June 6, 1939 FOREIGN PATENTS Number Country Date 120,304 GreatBritain Nov. 7, 1918 211,542 Great Britain Feb. 28, 1924

